'Thirty' in the Bible

And the space in which we came from Kadeshbarnea, until we were come over the brook Zered, was thirty and eight years; until all the generation of the men of war were wasted out from among the host, as the LORD sware unto them.

And the children of Israel wept for Moses in the plains of Moab thirty days: so the days of weeping and mourning for Moses were ended.